In hair curler roller constructions of the prior art steam is generated and passes through a foam covering sleeve which permits penetration on both the front and rear surfaces of the hair curler roller. However, since the foam material has a multitude of openings through the entire material the steam, if generated through a hollow core having holes or slots therein, will pass quickly through the open material and the steam heat will dissipate to the atmosphere. This occurs since the heat will not be maintained for a considerable period of time within the roller cover before radiating outwardly during and after the hair strands are being wound around the roller cover. Such an arrangement is found, for example, in U.S. Pat. No. 4,453,554 issued on Jun. 12, 1984.
In the past a group of heated hair curler rollers have been mounted in a housing having a single cover for the entire group of rollers so that when the cover was opened all the hair curlers were subject to cooling down, and a good part of the heat was dissipated even if it was possible to rapidly place all the curlers on the hair during the hair curling process. Such a drawback is evident in FIG. 8 of U.S. Pat. No. 4,627,452 issued on Dec. 9, 1986, and also shown in U.S. Pat. No. 4,658,114 issued on Apr. 14, 1987.